The Skin Phenotyping Core of the Skin Disease Research Center provides a wide array of histological, immunohistochemical, and molecular-based tools to characterize gross and microscopic morphology, functional features and gene expression in skin of mutant and genetically engineered laboratory animals. Special technical expertise within this core includes extensive knowledge of skin and hair follicle morphology essential for understanding the genotype/phenotype correlations;state of the art methods for gene expression studies at both mRNA and protein level specifically designed for mouse and human skin;and possession of a battery of original experimental approaches to the study of skin physiology in vivo. The Core will assist Center investigators as well as other researchers at Columbia in evaluating the significance of a phenotypic manifestation or unanticipated skin effects of a genetic mutation, drug, or other experimental manipulation;to understand the possible functions of genes and molecular pathways implicated in skin/hair phenotype development and to analyze skin expression patterns of genes of investigator's interest at the mRNA and protein level using immunohistochemistry and in situ hybridization. In addition, the Core will provide investigators with proof reading of and suggestions for Materials &Methods sections for publications and applications for extramural research funding utilizing skin phenotype analysis. The Skin Phenotyping Core also serves as a center of communication between investigators providing the ground for exchange of samples, antibodies, techniques and ideas. The Core brings investigators working in similar projects and techniques together thus reducing the costs and increasing efficiency of research.